In some wireless communication systems, periodic radio transmissions by a wireless communication terminal interfere with a companion device or accessory. In 3rd Generation Partnership Project (3GPP) Long term Evolution (LTE) Frequency Division Duplex (FDD) systems, for example, periodic physical uplink control channel (PUCCH), sounding reference signals (SRS) and physical uplink shared channel (PUSCH) transmissions, among others, from user equipment (UE) may create or cause interference in an associated hearing aid device or other EM-coupled devices, such as speakerphones, entertainment systems or public address systems. Transmissions on other wireless communication systems may cause similar interference. Generally, the severity of the interference depends on a many factors including the design of the victim system and coupling efficiency to the aggressor terminal. The most significant factors relevant to the interference from the perspective of aggressor terminal transmitter waveform design include: UE operating power; a difference between “ON” power of the UE when transmitting and “OFF” power of the UE when not transmitting; transition time and transition power profile (power vs. time) between and ON and OFF power levels; and the periodicity or more generally activity pattern, of the ON/OFF transitions. For LTE Time Division Duplex (TDD) systems in particular, dynamically scheduled PUSCH transmissions and ACK/NACK transmissions from the UE can also cause interference to the companion device or system due to the inherent uplink transmission periodicity introduced by the uplink/downlink (UL/DL) split (e.g., for the 8 DL+1 SS (special subframe): 1 UL subframe configuration with 1 ms subframes, the UE's UL transmissions are sent only for 1 ms every 10 ms).
U.S. Publication No. 2009/0003305 entitled “Method And Arrangement in a Telecommunication System” discloses mitigation of interference in non-UMTS audio equipment caused by bursty or intermittent transmissions. In US 2009/0003305, interference is reduced by introducing a randomization mechanism into the mapping of function of data packets onto the Hybrid Automatic Repeat Request (HARQ) processes, which in turn are mapped onto predefined sub-frames. Alternatively, US Publication No. 2009/0003305 discloses reducing interference by permuting HARQ transmission occasions without randomizing the selection of the HARQ process.
The various aspects, features and advantages of the invention will become more fully apparent to those having ordinary skill in the art upon careful consideration of the following Detailed Description thereof with the accompanying drawings described below. The drawings may have been simplified for clarity and are not necessarily drawn to scale.